[Yaesu] mark V sub receiver problem

[Federico Zanini IK3UMT]

Hi All
I own a new ft1000MP MK V

I have this behaviour with sub vfo b :

All bands are absolutely dead (no secondary s-meter reading neither any
signal heard) except for 7 , 10 and 14 MHz bands
where a constant S 9+10 noise is heard (like many electric discharges)

Any idea ??
Some macroscoping menu mistake (I hope) ????

Thanks
Federico